Before you consider sexual vibe, though, you have to be doing three other things very well:
a) Having fun
b) Being social and Making other people have fun
c) Making emotional connections with people and seeing if they meet your high standards.

For me, it is accomplished mainly through various kinds of screening and qualifying which is the bread and butter of what we call "Game". Both a) and b) can be done through state pumping.

When you are out, you must be having fun being social, making other people have fun, and making connections to see if people meet your standards. If you're not doing this yet, forget about sexual vibe, and focus on these things first.

On to sexual vibe.
There are three main ways that you can convey sexual vibe and take things smoothly to the next level.
1) Sexual Statements of Interest and Physical escalation rewards
2) Sexual Eye Contact and Voice tonality
3) Sexual state transference

1) When I first started in the community in 2003, I'd make girls laugh with my Cocky Funny attitude and teasing, but then when I went to escalate, things got REAL awkward. It took me about a month to realize that I was playing it too safe and that I was the one making it awkward. I had forgotten about the Showing interest verbally. And more importantly, I wasn't showing any interest with a sexual vibe. Mr. Holly Jolly Dancing Monkey routines pretty much.

A lot of guys think that we're not supposed to give compliments about girls' physical traits. I believed that too for a while. So I did standard screening and qualifying on personality traits ONLY. Which was great to build comfort but that can also lead to the dreaded FRIEND ZONE.

If you're a high value guy, which is the image you ought to be projecting if you're doing everything right, you still need more buy in for most girls (unless we're talking girls who are really stuck in their little ivory tower, in which case you would wait longer to pull out the sexual verbal game and do more qualifying and physical rewarding.

In general, after approaching and qualifying their personality traits, you need to tell them that you find them attractive, sexy, pretty, fucking hot!!! You can say "Not only do you have beauty, but you have brains too, I love it!!" Or you can be more direct and tell her how sexy her ass looks in those jeans....whatever.
The degree of directness here should be calibrated to the girl.
With some girls, you might even have to just say, while looking deep into her eyes, "I think... you are ... really... beautiful." But you really have to mean it.

As the interaction goes further and further, I go into hardcore sexual state and start escalating physically while blaming it on her:
Ex. "Its all your fault, why are you doing this to me? I am going to fuck you so hard you won't be able to walk tomorrow"

All of these sexual statements should be accompanied by some kind of physical escalation (pulling her towards you, kissing her neck, slowly running your hand up her back a slightly pulling her hair etc.) The degree and kind of physical escalation you apply depends on the type of girl and where you're at in the interaction.

But make sure that your escalation are rewards. That is, she should feel like she's won that physical touch for the reasons stated in your Sexual statement. Sexual statement= physical escalation (note. This is only used if comfort has been established)

2) There's not that much that I can convey through words about this, but I can't stress the importance of Laser Eye Contact Enough. The same goes for strong voice tonality. So practice practice practice.

Sometimes in settings that are relatively quiet and well-lit, good eye contact and tonality alone are enough to create massive attraction.
Id say the most important aspect of Eye Contact that separates the true pimps from the creepy dudes who look like child molestors is that you have to project your mood via state transferance. if you are in a sexual state, you imagine yourself fucking that girl you're talking to as you deeply look into her eyes, she will pick up the vibe naturally. If your a fun positive guy and that is truly your state of mind, then this feeling will be transferred via eye contact. This is all very powerful and the key to good eye contact (not trying to hold it in a deranged stare contest lol)

I would recommend that you wait until you are further along in the interaction before doing this. This is a huge reward for her, and she really has to earn it. When you do it at the right time, it's very powerful and should lead right into heavy physical escalation.